Brake-drum-truing tool



Oct. 29, 1929. F. E; BURKE 1,733,578

BRAKE DRUM TRUING TOOL Filed Sept. 8, 1925 4 Sheets-Sheet l I /0 fi i /2 g 4 lwmhbm w.

Oct. 29, 1929. F. E. BURKE I 1,733,578

BRAKE DRUM TRUING TOOL Filed Sept. 8, 1925 4 Sheets-Sheet 2 Oct. 29, 1929. F. E. BURKE BRAKE DRUM TRUING TOOL Filed Sept. 8, 1925 4 Sheets-Sheet 3 l I O 1 72 @72107" fifazzfezfi'zu%e Oct. 29, 1929. F, E BURKE 1,733,578

BRAKE DRUM TRUING TOOL Filed Sept. 8, 1925 4 Sheets-Sheet 4 3 Kmf mdlmw wl f,

' 1@ when Patented Oct. 29, 19.29 I

' UNITED STATES PATENT OFFICE -FRANK E. BURKE, OF CHICAGO, ILLINOIS v BRAKE-DRUM-TRUING 'rooL Application fl1ed September that a drum turned true in a lathe will,

when restored to the wheel, sometimes be out of true. Removal of the drum from the wheel for truing is, therefore, not only time-taking but, in'many instances, distinctly detri mental in defeatingthe very object sought. Among the objects of my invention are to provide a tool-mechanism by which a brakedrum may be trued while remaining in place upon the wheel; and to provide mechanism for such purpose which will be highly efiicient, eiiectively usable without particular skill on the part of the operator, readily handled and adjusted, and of simple, compact and inexpensive construction.

For attainment of these and other objects which will become apparent from the following specification taken in conjunction with the accompanying drawings, my invention consists in the combinations and features of construction and arrangement hereinafter set forth and claimed.

In the drawings, wherein I have illustrated a single embodiment of my invention for purposes of disclosure, Figure 1 is an elevation, with parts broken away, showing the tool in position of use; Fig. 2 is a diagrammatic perspective view, with parts distorted where need be for clarity, to depict in general the gear-trains employed; Fig. 3 is a horizontal section on the line 3-3 of Fig. 1 showing the upper stage of the. gearing; Fig. 4 is a section on the line 44 of Fig. 1 showing a lower stage of the gearing; Fig. 5 is a nearly-central vertical section on the line 55 of Fig. 3 and Fig. 6 is an elevation of the gearing, with parts broken away, and with the casing broken away on the line 6-6 of Fig. 3.

In the drawings, 10 represents an automos, 1925. Serial m. 54,923.

bile wheel carrying a brake-drum 11, these parts normally-providing in somewhat variant forms, a hub-structure 12 to which (and/or to spokes 13) the brake-drum is rigidly secured, with its braking surfaces of the flange 14 concentric with the hub-opening. One'of the purposes of brake-truing is to restore this concentricity, if lost through wear, other purposes being to remove scoring or other improper surface conditions of the m outer and/or inner faces of the flange.

By my invention I provide a truing tool that combines a centering member, enerally indicated at 15, having provision %or rigid attachment to the wheel so that it will extend along the axis of the wheel and accuratelycenter the dressing member which is generally indicated at 16, such dressing member being rotatable about the centering member to dress the brake-flange 14 concentrically with the wheel axis and being also movable axially toward the wheel to work progressively across the width of the flange 14.

In the specific construction shown, the centerin member comprises a stem 18 to be positloned coincidently with the axis of'the wheel and to carry the working parts of the mechanism. For attachmentto the wheel the stem is equi ped with centering cones, there being provi ed near the lower end of the stem a shoulder 19 beyond which is a threaded end portion 20, for receiving the cones. One cone member 21, screwed against the shoulder 19, will engage a suitable inner portion of the hub, while a second cone, 22, backed by a-nu't 23 .on the threaded end of the stem, will engage a suitable outer portion of said hub, thus to position the stem accuratel along the wheel axis and, by gripping the hu structure under the tension supplied by the nut 23, to secure the stem rigidly against rotation while the tool is in use. In commercial practice a few pairs of cones of proper dimensions will cooperate properly with the hubs of practically all commercial makes of brakedrum carrying wheels, and the easy removability of the cones enables quick substitution to be made.

The upper portion of the stem '18 rigidly carries the frame-structure or gear-housing j its bearing in the shell, generally indicated at 25, by which all of the working parts of the device are directly or indirectly carried. In the particular construction shown, the apertured top of they casng surrounds a reduced screw stud 26 and rests on the shoulder 27 of the stud, nut 28 securing the shell fixedly to the stem.

The dressing member 16 (or pair of such members) will be carried by a lateral arm 30 which is to be rotated about the stem and also fed axially downward along the stem in its dressing operation. Specifically, such dressing members may be cutting tools of any suitable design carried by respective holders 1'? which, in any simple fashion, are adjustably secured on the arm 30 so that, if desired, both tools may be used for simultaneously truing the inner and outer surfaces of the drumflange. The tool-carrying arm 30 projects from the lower end of a tool-operating sleeve 31 which extends into shell 25 through a bottom opening of the shell and which is rotatable about and axially movable along the stem 18. The means for imparting to the stem both of its stated movements are carried by. the shell and power is preferably supplied by an electric motor 32 which is shown as a well known design of electric-drill motor, the power-transmitting connections between said motor and the sleeve 31 constituting one available arrangement which gives substantial and novel advantages.

In the specific construction shown (the general arrangement whereof may best be understood from Fig. 2) the sleeve 31 is rotated by gearing and is fed downwardly by a nut, the nut being preferably rotated by power transmitting connections from the stated gearing, which connections preferably include clutch mechanism by which the nut may be effectively disconnected from the motor-driven gear, for stopping the axial feed of the sleeve and for permitting retraction of the sleeve while the electric motor is at a standstilli In the particular embodiment shown the sleeve 31 is provided with a coarse external thread 34 which is engaged by a nut 35 which is rotatably mounted in the'frame or shell 25 but is' held against axialdisplacement. This arrangement provides for a most direct axial movement of the stem, although other operative associations of a feeding nut and the axially slidable stem might be employed.

To drive the screw sleeve 31 in rotation,.it is equipped with a gear 36 through which it may slide but by which it is turned, such gear also being held against axial displacement by casing 25 and having a key projection 37 slidably engaging in a longitudinal slot 38 formed in the screw sleeve.

In operation both the sleeve and the nut are rotated in the same direction, but with slightly different angular velocities, the slight difference in rate of rotation resulting in a slow axial progression of the screw sleeve through the nut. Thus with a left hand thread, as shown, on the screw sleeve, the nut 35 is geared to rotate slightly faster than the gear 36 to eltect the desired slow downward feed of the stem.

The electric motor 32 drives the sleeveturning gear 36 through a suitable speedreducing train, best shown in Fig. 3. Motor shaft 40 carries pinion 41 meshing with gear 42 which carries pinion 43 meshing with the sleeve-rotating gear 36, for suitable speed reduction. The power-transfer connections between gear 36 and nut 35 are desirably inclusive of the disconnection clutch, as stated, and a manually operating retracting gear, the specific arrangement shown being as follows:

- The gear 36 meshes with transfer pinion 45 which cooperates with an axially'slidable shaft 46, such shaft having splined engagement as at 47 with the pinion 45so that the two will rotate together, and pinion 45 being positioned against axial displacement by its bearing on the casing. Such shaft 46 carries one jaw 48 of the clutch, the other jaw 49 being rigid with a second transfer pinion 50 through wh ch the shaft 46 loosely extends. Spring 51 encircling the upper portion of shaft 46, where it protrudes above the body of shell 25, normally holds the clutchmembers engaged, and in this condition the two transfer work pinions are rotated in unison. pressed toe-Iutclrdisengaging position and there latched by a spring-latch 52, as shown in Fig. 2, thus to free the transfer pinion 50 from connection with the power-driven gear train. The secondary transfer pinion 50 is in train with the feeding nut 35, through an idler pinion 55 (for correction of rotational direction) and an intermediate gear 56, the latter being provided with means, accessible from the exterior of the casing, by which said intermediate gear and consequently the nut 35 may be manually rotated to effect a quick retraction of the screw-sleeve 31 to raised position. Specifically,intermediate gear 56 has a hub 57 projecting above the body of the casing and provided with square clutchprojections 58 to receive coacting teeth 59 of a knurled resetting knob 60 which is slidable on a stem-part 61 projecting above the hub 57, and is normally held in raised or idling position by a spring 62 interposed between the hub and the handle and cncircling said stem. It will be apparent that, with the parts in the position shown in Fig. 2 (i. c. with' the power-transfer clutch 49 in open position) the operator may depress the resetting knob 60 to engage clutch teeth 58 and 59 and then may rotate the feed nut 35 by turning the knob 60. Also it will be apparent that, with the sleeve-rotating gear 36 standing still (as it will be if the motor 32 The shaft 46 may, however, be decasing is idle) the course thread on the screw sleeve 31 will permit it to be rapidly retracted by such manual rotation, in a propriate direction, of the feed nut 35. A so it will be clear 7 that, except for the desirability of providing with the knock out arm 65, to be carried axially by the sleeve but without rotation. The outer end of this arm carries a vertically adj ustable' striker rod 66, secured in the split clamp 67 of the arm and vertically registering with the slidable clutch-operating shaft 46 of the transfer gear. The inner end of the arm is integral with a ring 68 fitting in a groove 69 near the upper end of the screw stem, and the arm is guided vertically and retained against rotation by the walls'of the slot 70 cut in. the barrel portion of the shell or frame 25.

Of course the shell 25 may take any suitable form to house and position the parts heretofore described, but for manufacturing advantages its body portion 25 is preferably built up of horizontal sections 72, 73 and 74,

providing gear-receiving compartments, the horizontal walls of which hold the several gear members against vertical displacement, these sections being bolted together marginally as at 76, while the cylinder portion 25 is integral with the top section 74 of the body and is of suitable height to accommodate full retraction of the screw sleeve.

In rsum: The cones 21 and 22, making clamping engagement with the wheel hub, afford self-centering means for positioning the stem 18 of the centering member axially on the brake-drum-carrying wheel. To dress the drum-flange l4 externally and/or internally to true concentricity and cylindrical form the cutters 16 are rotated about said stem atadequate cutting speed and at the same time fed slowly downward across the Width of the drum-flange. To this end the tool-carrying arm 30 is secured to the operating sleeve 31 which surrounds stem 18 and may be both fed along and rotated relatively to said stem by the gearing contained in the frame or gear 25 which itself is rigidly secured to the stem-18. When electric motor 32 is in operation and clutch 4849 is engaged, power is transmitted through the reducing gearing 41, 42, 43, and 36 to rotate the sleeve 31, which is slidable axially through the gear 36 that drives it. Power transferred from said gear 36 through the train 45 (clutch 48, 49) 50, 55, 56, 35 serves to rotate the nut 35 which makes engagement with the coarse thread 34 on the exterior of the operating sleeve 31 and (rotative directions being as shown by the arrows and nut 35 having an angular velocity slightly greater than gear 36) the operating sleeve is s owly fed downwardly along the stem 18. As the cutters approach the bottom of the brake-drum flange, the suitably adjusted striker rod 66 of the knock-out means, traveling axially with the stem, will strike the end of clutch-shaft 46, opening the clutch (which is automatically latched in open position by the spring catch 52) to break,the power-connections for the feed-nut 35. Of course the motor may thereupon be stopped by the operator, and to secure quick restoration of the operating sleeve to raised position, the operator will manually depress the resetting knob 60, engaging its clutch teeth with those of the intermediate gear 56 so that by turning the knob the .feed nut 35 will be rotated Without rotation of the sleeve-turning gear 36. The

coarse thread of the operating sleeve 31 enables it thus to be manually adjusted rapidly to retracted position or position for fresh out.

While I have herein described in some detail a specific embodiment of my invention which I believe to be particularly desirable and some of the details of which I may claim for-its specific advantage, it will be apparent that numerous changes in construction and arrangement of parts might be made without departure from the spirit of my invention and within the scope of the appended claims.

I claim:

1. An automobile-brake-drum truing mechanism, comprising. a centering stem having provision for axially-extending centered attachment to the drum-carrying wheel, a drumflange-dressing member, a sleeve carrying the same and movable rotatively about 1 and axially with respect to said stem, gear means to impart rotation to said sleeve, and a threaded feeding member rotatable in the same direction as said sleeve, operated by said gear means, to impart slow axial feed to said sleeve.

2. An automobile-brake-drum-truing mechanism, comprising a centering member having provision for centered attachment to the drum-carrying wheel, a drum-flange-dressing member, a sleeve carrying the same and movable both rotatively and axially with respect to said centering member, gear means to impart rotation to said sleeve, a feed-nut operatively connected with said sleeve to feed it axially, and operatively associated means for roe tating said gear means and for rotating said feed nut in the same direction and at such rates as to effect relatively-rapid rotation of structure non-rotatably mounted on said cen tering member, a drum-flange-dress ing memher, a rotatable and axially-movable part carrying said dressing member and guided by said centering member and entering said frame, and operating means for said part carried within said frame, said operating means comprising gear means to impart rotation to said part, and a threaded feeding nut operatively associated with said part and with said gear means to impart slow axial feed thereto.

4. An automobile brake drum truing mechanism, comprising a centering member having provision for centered attachment to the drum-carrying wheel, a frame structure non-rotatably mounted on said centering member, a drum-flange-dressing member, a rotatable and axially movable part carrying said dressing member'and guided by said.

centering member and entering said frame, and operating means for said part carried within said frame and comprising gear means to impart rotation to said part, a

threaded feeding nut operatively associated with said part to impart slow axial feed thereto, and power-transfer means operated directly from said gear means to drive said nut.

5. An automobile-brakev-drum truing mechanism, comprising 'a centering stem having provision for axially-extending, centered attachment to the drum-carrying wheel; a drum-,fiange-dressing member, a threaded sleeve carrying the same and movable rotatively about and axially with respect to said stem, a frame member fixedly carried by said stem and into which said sleeve extends, a nut positioned by the frame co-acting with the threaded sleeve, a gear on the frame for rotating said threaded sleeve, and means for driving said nut and gear in like direction at different rates of speed to effect slow axial feed of said sleeve through said nut as said sleeve is being rotated by said gear. v

6. In a device of the character described,

the combination with a centering stem, and

- a tool-carrying sleeve axially slidable and rotatable thereon, a sleeve driving motor,

means driven thereby to rotate the sleeve, means to axially feed-the sleeve comprising power transfer connections between said sleeve and said driving motor including a clutch, and means operated by said sleeve to automatically open said clutch.

7. In a device of the character described,

the combination with a centering stem and a tool carrying screw-sleeve slidable and rotatable with respect to said stem, a sleeve rotating gear, a "sleeve feeding nut, and

means, including a drive connection between said sleeve rotating gear and nut, for driving said gear and nut in like direction at slightly different angular speeds, to effect slow feed ofthe sleeve during its relativerapid rotation.

tably movable with respect to the centering stem, a sleeve-rotating gear, means to drive it, a sleeve-feeding nut, power-transfer connections for driving said nut from said gear and including a clutch, and means operated by said sleeve for automatically disconnecting said clutch to stop the feeding movement of the sleeve.

10. In a device of the character described,

a centering stem, a casing non-rotatably carried thereby, a tool-carrying threaded sleeve entering said casing and axially and rotatably movable with respect to the centering stem, a sleeve-rotating gear, means to drive it, a sleeve-feeding nut, power-transfer connections for driving said nut from said gear and ihcludin a clutch, means for disconnecting said 0 utch to free the nut from power-transfer connection with the gear, and means for backwardly rotating said nut withoutrotating said gear.

11. In a device of the character described, the combination of a centering stem having provision for centered attachment to the wheel, a casing non-rotatably carried thereby, a coarsely-threaded tool-carrying sleeve rotatably and axially movable with respect to the centering stem and entering said cas ing, an electric driving motor supported from said casing, a sleeve-rotating gear, re ducing gearing between said motor and sleeve-rotating gear, a sleeve-feeding nut, power-transfer connection from said gear to said nut including a clutch and also an intermediate gear that is in constant mesh with the nut, means carried by said sleeve for automatically disconnecting said clutch, and manually operatable means associated with said intermediate gear for imparting reverse movement to said nut, quickly to retract said sleeve without turning said sleeverotating gear.'-

a. In an automobile-brake-drum truing mechanism, an attachment member having nally threaded sleeve member rotatable.

around and movable axially of said attachment member and fixedly carrying said dressing means, gear mechanism for imparting, rotatable movement to said sleeve member, an

axially immovable feed member rotatable with and in the direction of said sleeve member and having a threaded portion engaging the externalthread of said sleeve, and means 5 including a clutch for eflecting an independent rotative movement of said feed member to cause axial movement of said sleeve mem- 13. In an automobile-brake-drum truing m mechanism, drum-fiange-dressing means including a rotatable and axially movable externally threaded support, means for rotating said support, an axially immovable axial feed member engaging the external/threaded portion of said support, means for imparting rotary motion to said feed member, and power-transfer means for operatively connecting said support rotating means and said member rotating means and arranged to cause said latter means to rotate relatively faster than said support rotating means to effect axial movement of said support.

14. In an automobile-brake-drum truing mechanism, drum flange-dressing means ineluding a rotatable and axially movable externally threaded support, means for rotating said support, an axially immovable axial feed member engaging the external threaded portion of said support, means for imparting rotary motion to said feed member, and

power-transfer means for operatively connecting said support rotating means and said member rotating means and arranged to cause said latter means to rotate relatively faster than said support rotating means to effect axial movement of said support, and manual means including a clutch for disconnecting said feed member rotating means to permit a manual adjustment of said support, and an adjustable stop device for controlling the operation of said disconnecting means automatically.

FRANK E. BURKE. 

